A method and system for attitude calibration of an array direction finding antenna

Abstract

The application discloses a kind of attitude calibration method and system of array direction-finding antenna, the method includes the following steps: accurately measuring the real coordinates of array direction-finding antenna center point A;Positioning label is placed in the periphery of array antenna, measures N group real coordinates of the positioning label and N group direction angle θ and the elevation angle of the positioning label relative to the array antenna, and the measured coordinates P of N group positioning label are calculated;The coordinate P' after rotation of each measured coordinate P point is calculated;Using N group P and the coordinate of P', the rotation matrix R is calculated;Using the rotation matrix R obtains the attitude angle of array antenna.The application uses positioning label to calibrate the attitude of array direction-finding antenna, the method is simple to operate, does not need professional equipment, and can greatly improve the efficiency of array antenna calibration.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication positioning technology, and particularly relates to a method and system for calibrating the posture of an array direction finding antenna. BACKGROUND

[0002] With the increasingly wide application scenarios of indoor positioning and the huge commercial value, various positioning technologies emerge, such as RSSI-based WIFI or Bluetooth Beacon positioning, UWB positioning, etc. Among these positioning technologies, the method of positioning through array direction finding technology is attracting more and more attention because of the small number of required base stations and flexible base station deployment. The Bluetooth 5.1 specification explicitly supports the measurement of Angle of Arrival (AoA) and Angle of Departure (AoD), which greatly improves the accuracy of Bluetooth indoor positioning by measuring the direction information of the signal. On the other hand, by adding direction finding technology to UWB positioning, three-dimensional positioning can be achieved using a single base station, greatly reducing the number of base stations compared to range-based methods.

[0003] Although the positioning method based on array direction finding can greatly reduce the number of deployed base stations compared to range-based positioning methods, it is more sensitive to the posture of the array antenna and requires high accuracy of the posture, i.e., the posture error of the array antenna may cause a large positioning deviation. Currently, it is strictly required to install the array antenna according to a certain fixed posture, or to manually measure the posture using professional equipment, thereby reducing the error caused by the posture.

[0004] In order to eliminate the error caused by the installation posture of the array antenna, it is necessary to strictly require the installation posture of the array antenna, but it is too difficult to use in actual use and cannot be widely used. Currently, manual measurement of the posture of the array antenna is time-consuming and requires professional equipment, which is costly. SUMMARY

[0005] The purpose of the present application is to provide a posture calibration method and system that can greatly improve the efficiency of array antenna calibration and solve the problems of difficult array antenna posture calibration process, time-consuming and high cost.

[0006] In order to achieve the above-mentioned purpose of the present application, a method for calibrating the posture of an array direction finding antenna is provided, which comprises:

[0007] accurately measuring the real coordinates of the center point A of the array antenna;

[0008] placing positioning labels around the array antenna, measuring the real coordinates Pr of N groups of the positioning labels and the direction angle θ and the pitch angle φ of N groups of the positioning labels relative to the array antenna

[0009] Obtain the measurement coordinates P(x,y,z) of N sets of positioning tags;

[0010] Obtain the rotated coordinates P'(x′,y′,z′) of each of the measured coordinate points P;

[0011] Calculate the rotation matrix R using the N sets of coordinates of P and P';

[0012] The attitude angle of the array antenna is obtained using the rotation matrix R.

[0013] Optionally, the elevation angle of the positioning tag relative to the array antenna The range is from 20 degrees to 50 degrees.

[0014] Optionally, the array antenna collects data and uploads it to a server, whereby the server performs direction finding processing on the positioning tag to obtain the azimuth angle θ and elevation angle.

[0015] The process of obtaining the measurement coordinates P of the N sets of positioning tags includes:

[0016] Using the true coordinates (x0, y0, z0) of the center point A of the array direction-finding antenna (set 1), and N sets of the azimuth and elevation angles... And the true coordinates of the N sets of positioning tags [(Xr1,Yr1,Zr1),(Xr2,Yr2,Zr2)……(Xr N ,Yr N ,Zr N Calculate the measured coordinates P of the N sets of positioning tags;

[0017] If the center point A(x0,y0,z0) of the array antenna is translated to (0,0,z0), then the true coordinates Pr of the positioning tag will also change accordingly:

[0018] [(Xr1-x0,Yr1-y0,Zr1), (Xr2-x0,Yr2-y0,Zr2)……(Xr N -x0,Yr N -y0,Zr N )],

[0019] Recorded as:

[0020] [(X1,Y1,Z1),(X2,Y2,Z2)……(X N ,Y N Z N )]

[0021] When the array antenna is located at (0,0,z0), the height of the positioning tag is Zi. Therefore, the height difference between the positioning tag and the array antenna is z0-Zi, calculated using the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinates P:

[0022]

[0023] Obtain the measurement coordinates P of the N sets of positioning tags:

[0024] [(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )).

[0025] The process of obtaining the rotated coordinates P' of each measured coordinate point P includes:

[0026] A line segment APr is obtained by connecting the center point A of the array direction-finding antenna with the real coordinate Pr of the positioning tag. The horizontal plane is rotated by the rotation matrix R to obtain a plane. The intersection point of the line segment APr and the plane is P'. Therefore, P' is the point P after being rotated by the rotation matrix R.

[0027] Using the coordinates of point A (0,0,z0) and point P (x1,y1,z1), we obtain:

[0028]

[0029] The coordinates of P' are calculated as (x′1, y′1, z′1) based on the actual coordinates Pr(X1, Y1, Z1) of the positioning tag and the length of AP'.

[0030] From the actual coordinates of the N sets of positioning tags, obtain the N sets of P' coordinates:

[0031] [(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )).

[0032] The process of obtaining the rotation matrix R using the N sets of coordinates of P and P' through the SVD decomposition method includes:

[0033] N sets of coordinates of point P:

[0034] SP=[(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )] = [Sp1,Sp2,……SpN ];

[0035] N sets of coordinates of point P':

[0036] SP'=[(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )]=[Sp′1,Sp′2,…Sp′ N ];

[0037] The average of N sets of P coordinates: The average of N sets of P' coordinates:

[0038] Normalize all points:

[0039]

[0040] Calculate the covariance matrix:

[0041] S = AB T

[0042] Where A and B represent the terms a i and b i The matrix consists of columns and has a dimension of 3×N.

[0043] Calculate the singular value decomposition of matrix S, S = UΣV T Then the rotation matrix R:

[0044]

[0045] Here, det represents the calculation of the determinant of the matrix.

[0046] The process of obtaining the attitude angle of the array antenna using the rotation matrix R includes: calculating the attitude angle using a formula.

[0047] Where, θ yam This indicates the angle by which the array antenna rotates around the Z-axis of the map coordinate system;

[0048] θ Pitch This indicates the angle by which the array antenna rotates around the X-axis of the map coordinate system;

[0049] θ roll This indicates the angle by which the array antenna rotates around the Y-axis of the map coordinate system;

[0050] r mn This represents the term in the m-row, n-column rotation matrix R.

[0051] Optionally, the measurement coordinates of the positioning tag can be calibrated using a rotation matrix R:

[0052] When the base station is located at point A(0,0,z0), the orientation angle and elevation angle of the positioning tag relative to the base station are obtained through direction finding. Calculate the measured coordinates P of the positioning tag:

[0053]

[0054] Where z is the height of the positioning label;

[0055] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0056]

[0057] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning label is located;

[0058] Based on the actual location of the base station, the actual location of the positioning tag is calculated as (X1+x0,Y1+y0,z).

[0059] The present invention also discloses an attitude calibration system for an array direction-finding antenna, comprising: a direction-finding module, a calculation module, and an attitude angle acquisition module;

[0060] The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates of the positioning tag, and the azimuth angle θ and elevation angle of the positioning tag relative to the array antenna.

[0061] The calculation module is used to accurately calculate the measured coordinates P of the positioning tag and the rotated coordinates P' of the measured coordinates P using the data measured by the direction finding module.

[0062] The attitude angle acquisition module is used to obtain the rotation matrix R by using the coordinates of P and P' calculated by the calculation module.

[0063] The present invention also includes a computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the method described above.

[0064] Compared to existing technologies, this invention utilizes the coordinates of a set of array antenna center point A, the actual coordinates of N sets of positioning tags, and the azimuth angle θ and elevation angle of the N sets of positioning tags relative to the array antenna. By rotating and calculating, N sets of measured coordinates and N sets of rotated coordinates are obtained, and then the rotation matrix is ​​calculated, ultimately yielding the attitude angles. Using positioning tags to calibrate the attitude of the array direction-finding antenna and obtain the attitude angles is a simple method that does not require third-party specialized equipment. This significantly improves the efficiency of array antenna calibration and solves the problems of high difficulty, time consumption, and high cost in array antenna attitude calibration. Attached Figure Description

[0065] Figure 1 This is a schematic diagram of the array antenna coordinate system in an embodiment of the present invention;

[0066] Figure 2 The flowchart below illustrates the attitude calibration method for the array direction-finding antenna in this embodiment of the invention. Figure 1 ;

[0067] Figure 3 The flowchart below illustrates the attitude calibration method for the array direction-finding antenna in this embodiment of the invention. Figure 2 ;

[0068] Figure 4 This is a schematic diagram showing the position of P in the coordinate system in an embodiment of the present invention;

[0069] Figure 5 This is a schematic diagram showing the position of each point in the coordinate system after rotation in an embodiment of the present invention. Detailed Implementation

[0070] The attitude calibration method and system for the array direction-finding antenna of the present invention will be described in more detail below with reference to the schematic diagrams, which illustrate preferred embodiments of the invention. It should be understood that those skilled in the art can modify the invention described herein while still achieving the advantageous effects of the invention. Therefore, the following description should be understood as being of general knowledge to those skilled in the art and is not intended to limit the invention.

[0071] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0072] The attitude calibration method for the array direction-finding antenna provided by this invention requires measuring the attitude relationship of the array antenna relative to the map reference coordinate system, such as... Figure 1 As shown, in this embodiment, to facilitate the description of the installation attitude of the array direction-finding antenna, a Cartesian three-dimensional coordinate system with the array antenna as the reference is defined, taking a uniform circular array as an example:

[0073] The origin of the coordinate system is the center point of the uniform circular array;

[0074] The line connecting the first array element to the center of the uniform circular array is the x-axis of the coordinate system, and the direction from the center of the uniform circular array to the first array element is the positive direction.

[0075] The straight line perpendicular to the uniform circular array and passing through the origin of the coordinate system is the z-axis, and the direction of the array antenna toward the ground is the negative direction of the z-axis;

[0076] The y-axis is perpendicular to the xz plane and passes through the origin of the coordinate system.

[0077] Define the map reference coordinate system as (which can be combined with...) Figure 4 ):

[0078] The X-axis, Y-axis, and origin are based on the X-axis, Y-axis, and origin of the map;

[0079] The Z-axis is defined as the direction perpendicular to the horizontal plane.

[0080] The installation attitude of the array direction-finding antenna is described by Euler angles with a rotation sequence of ZYX. That is, the coordinate system of the array antenna initially coincides with the map reference coordinate system, and rotates around ZYX in sequence to generate azimuth, pitch and roll.

[0081] Azimuth (yaw): The angle by which the array antenna rotates around the Z-axis;

[0082] Pitch: The angle by which the array antenna rotates around the X-axis;

[0083] Roll angle: The angle at which the array antenna rotates around the Y-axis.

[0084] The attitude calibration method provided by this invention aims to obtain accurate attitude angles, namely azimuth, pitch, and roll data. Please refer to... Figures 2-3 The attitude calibration method for the array direction-finding antenna of the present invention will be described in detail below. The method includes the following steps:

[0085] S1. Accurately measure the true coordinates of the center point A of the array antenna;

[0086] S2. Place positioning tags around the array antenna, and measure the true coordinates Pr of N sets of positioning tags, as well as the azimuth angle θ and elevation angle of N sets of positioning tags relative to the array antenna.

[0087] S3. Obtain the measurement coordinates P of the N sets of positioning tags;

[0088] S4. Obtain the rotated coordinates P' of each measured coordinate point P;

[0089] S5. Calculate the rotation matrix R using the coordinates of P and P' in the N sets;

[0090] S6. Obtain the attitude angle of the array antenna using the rotation matrix R.

[0091] Specifically, in step S1, the true coordinates of the center point A of the array antenna on the map are accurately measured as (X0, Y0, Z0).

[0092] In step S2, a positioning tag is placed at a certain position below the array antenna, and the actual coordinates Pr of the positioning tag on the map are accurately measured and recorded as (Xr1, Yr1, Zr1).

[0093] In this embodiment, preferably, the pitch angle of the tag relative to the array antenna can be between 20 and 50 degrees. In actual measurement, other angles may also be used.

[0094] The array antenna collects data and uploads it to the server. The server performs direction finding processing on the tag to obtain the azimuth angle θ and elevation angle of the tag relative to the array antenna.

[0095] Move the location tag to one position and repeat N times, where N is greater than or equal to 3, and spread the different positions as far apart as possible.

[0096] The following data was obtained:

[0097] The coordinates (x0, y0, z0) of the center point of the array antenna 1;

[0098] N sets of azimuth and pitch angles:

[0099] The true coordinates of N sets of location tags [(Xr1,Yr1,Zr1),(Xr2,Yr2,Zr2)……(Xr N ,Yr N ,Zr N )).

[0100] In other embodiments, N tags can be placed and data can be collected simultaneously to save calibration time.

[0101] Specifically, in step S3, the coordinates of the measured coordinates P of the N sets of positioning tags are calculated:

[0102] For ease of calculation, the coordinates of the array antenna center point (x0, y0, z0) are shifted to (0, 0, z0), and the actual coordinates of the positioning tag also become:

[0103] [(Xr1-x0,Yr1-y0,Zr1),(Xr2-x0,Yr2-y0,Zr2)......(Xr N -x0,YrN -y0,Zr N )]

[0104] Recorded as:

[0105] [(X1,Y1,Z1),(X2,Y2,Z2)……(X N ,Y N Z N )]

[0106] in:

[0107] Xi = Xri - x0

[0108] Yi = Yri - y0

[0109] Zi = Zri

[0110] Since Zri is a precise measurement, Zi is also a precise measurement.

[0111] Please refer to Figure 4 When the array antenna is located at (0,0,z0), the height of the positioning tag is Zi. Therefore, the height difference between the positioning tag and the array antenna is z0-Zi. This difference is determined by the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinates P:

[0112]

[0113] Therefore, we can obtain the measurement coordinates P of N sets of positioning tags:

[0114] [(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )).

[0115] In step S4, the coordinate set of the positioning tag measurement point P after rotation by the rotation matrix R is calculated:

[0116] Please refer to Figure 5 In this embodiment, all coordinates in the figure are values ​​in the map coordinate system. The coordinates of the center point A of the array antenna in the figure are (0,0,z0), and Pr(X1,Y1,Z1) are the position coordinates of the actual position of the positioning tag after the same translation. The ideal attitude of the array antenna is parallel to the map reference coordinate system. The actual attitude of the array antenna is a rotation angle compared with the ideal attitude. It is assumed that the actual attitude of the array antenna is obtained by rotating the ideal attitude around point A according to the rotation matrix R. Point O is the origin of the map coordinate system, O' is the point after rotating point O by the rotation matrix R, and the plane L' parallel to the array antenna and passing through point O is also the plane obtained by rotating the horizontal plane L by the rotation matrix R.

[0117] The direction angle θ and elevation angle are measured by the array direction-finding antenna. Calculate the measured coordinates P(x1, y1, z1) of the positioning tag. Since P and Pr are located on the same horizontal plane, z1 = Z1. P' is the intersection of the line APr and the plane L'. Also, the direction angle θ and pitch angle of Pr relative to point A are calculated. The direction angle θ and pitch angle of point P relative to point A They are the same. P' is a point on the straight line APr and lies on the plane L'. Therefore, the position of P' relative to the array antenna coordinate system is the same as the position of P relative to the map coordinate system. So P' is also the point after P is rotated by the rotation matrix R.

[0118] Therefore:

[0119]

[0120] Using the coordinates of point A (0,0,z0), the actual coordinates of the positioning tag Pr (X1,Y1,Z1), and the length of AP', calculate the coordinates of P' (x′1,y′1,z′1).

[0121] Furthermore, from the N sets of coordinates mentioned above, we obtain N sets of rotated coordinates of point P:

[0122] [(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )]

[0123] That is, the coordinate set:

[0124] SP=[(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )] = [Sp1,Sp2,……Sp N ]

[0125] The coordinate set of P after rotation by rotation matrix R:

[0126] SP'=[(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )]=[Sp′1,Sp′2,…Sp′ N ].

[0127] In step S5, based on the above, in one embodiment, the rotation matrix R can be obtained through the SVD decomposition method:

[0128] Calculate the average of two coordinate sets:

[0129]

[0130] Normalize all points:

[0131]

[0132] Calculate the covariance matrix:

[0133] S = AB T

[0134] Where A and B are respectively represented by a i and b i The matrix consists of columns and has a dimension of 3×N.

[0135] Calculate the singular value decomposition of matrix S: S = U∑V T Then the rotation matrix R can be calculated using the following formula:

[0136]

[0137] Where det represents the determinant of the matrix, and V is the matrix S. T The matrix formed by the eigenvectors of S.

[0138] In step S6, assume R is:

[0139]

[0140] Euler angles are calculated using the following formula:

[0141]

[0142] Furthermore, in this embodiment of the invention, the method further includes calibrating the measurement coordinates of the positioning tag using a rotation matrix R, as follows:

[0143] Assuming the base station is located at point A(0,0,z0), the orientation angle and elevation angle of the positioning tag relative to the base station are obtained through direction finding. Then the measured coordinates P of the positioning tag can be calculated:

[0144]

[0145] Where z is the height of the positioning label;

[0146] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0147]

[0148] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning tag is located;

[0149] Based on the actual location of the base station, calculate the actual location of the positioning tag: (X1+x0,Y1+y0,z).

[0150] This invention also provides an attitude calibration system for an array direction-finding antenna, comprising: a direction-finding module, a calculation module, and an attitude angle acquisition module;

[0151] The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates of the positioning tag, and the azimuth angle θ and elevation angle of the positioning tag relative to the array antenna.

[0152] The calculation module is used to accurately calculate the measured coordinates P of the positioning tag and the coordinates P' of the measured coordinates P after rotation using the data measured by the direction finding module;

[0153] The attitude angle acquisition module is used to obtain the rotation matrix R by using the coordinates of P and P' calculated by the calculation module.

[0154] The direction-finding module is specifically used to obtain N sets of heading and pitch angles:

[0155] The true coordinates of N sets of location tags [(Xr1,Yr1,Zr1),(Xr2,Yr2,Zr2)……(Xr N ,Yr N ,Zr N )).

[0156] The calculation module is also used to obtain the measured coordinates P and the rotated coordinates P' of N sets of positioning tags.

[0157] The calculation module is specifically used to obtain the measurement coordinates P of N sets of positioning tags in the following form:

[0158] By shifting the coordinates of the center point (x0, y0, z0) of the array antenna to (0, 0, z0), the true coordinates of the positioning tag also become:

[0159] [(Xr1-x0,Yr1-y0,Zr1),(Xr2-x0,Yr2-y0,Zr2)......(Xr N -x0,Yr N -y0,Zr N )]

[0160] Recorded as:

[0161] [(X1,Y1,Z1),(X2,Y2,Z2)……(X N ,Y N Z N )]

[0162] in:

[0163] Xi = Xri - x0

[0164] Yi = Yri - y0

[0165] Zi = Zri

[0166] Since Zri is a precise measurement, Zi is also a precise measurement.

[0167] Please refer to Figure 4 When the array antenna is located at (0,0,z0), the height of the positioning tag is Zi. Therefore, the height difference between the positioning tag and the array antenna is z0-Zi. This difference is determined by the azimuth angle θ and the elevation angle. Determine the coordinates of the location tag's measurement coordinates P:

[0168]

[0169] Therefore, we can obtain the measurement coordinates P of N sets of positioning tags:

[0170] [(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )).

[0171] The calculation module is specifically used to obtain N sets of rotated coordinates P' in the following manner:

[0172] The coordinates of the center point A of the array antenna are (0,0,z0), and Pr(X1,Y1,Z1) are the coordinates of the actual position of the positioning tag after the same translation. The ideal attitude of the array antenna is parallel to the map reference coordinate system. Compared with the ideal attitude, the actual attitude of the array antenna has a rotation angle. It is assumed that the actual attitude of the array antenna is obtained by rotating the ideal attitude around point A with rotation matrix R. Point O is the origin of the map coordinate system, and O' is the point after rotating point O with rotation matrix R. The plane L', which is parallel to the array antenna and passes through point O, is also the plane obtained by rotating the horizontal plane L with rotation matrix R.

[0173] The direction angle θ and elevation angle are measured by the array direction-finding antenna. Calculate the measured coordinates P(x1, y1, z1) of the positioning tag. Since P and Pr are located on the same horizontal plane, z1 = Z1. P' is the intersection of the line APr and the plane L'. Also, the direction angle θ and pitch angle of Pr relative to point A are calculated. The direction angle θ and pitch angle of point P relative to point A They are the same. P' is a point on the straight line APr and lies on the plane L'. Therefore, the position of P' relative to the array antenna coordinate system is the same as the position of P relative to the map coordinate system. So P' is also the point after P is rotated by the rotation matrix R.

[0174] Therefore:

[0175]

[0176] Using the coordinates of point A (0,0,z0), the actual coordinates of the positioning tag Pr (X1,Y1,Z1), and the length of AP', calculate the coordinates of P' (x′1,y′1,z′1).

[0177] Furthermore, from the N sets of coordinates mentioned above, we obtain N sets of rotated coordinates of point P:

[0178] [(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )]

[0179] That is, the coordinate set:

[0180] SP=[(x1,y1,z1),(x2,y2,z2)……(x N ,y N ,z N )] = [Sp1,Sp2,……Sp N ]

[0181] The coordinate set of P after rotation by rotation matrix R:

[0182] SP'=[(x′1,y′1,z′1),(x′1,y′1,z′1)……(x′ N ,y′ N ,z′ N )]=[Sp′1,Sp′2,…Sp′ N ].

[0183] The attitude angle acquisition module is specifically used to obtain the rotation matrix R according to the following method.

[0184] Calculate the average of two coordinate sets:

[0185]

[0186] Normalize all points:

[0187]

[0188] Calculate the covariance matrix:

[0189] S = AB T

[0190] Where A and B are respectively represented by a i and b i The matrix consists of columns and has a dimension of 3×N.

[0191] Calculate the singular value decomposition of matrix S: S = U∑V T Then the rotation matrix R can be calculated using the following formula:

[0192]

[0193] Where det represents the determinant of the matrix, and V is the matrix S. T The matrix formed by the eigenvectors of S.

[0194] Furthermore, it also includes a calibration module, which is used to calibrate the measurement coordinates of the positioning tag using a rotation matrix R.

[0195] Specifically, the calibration module is calibrated in the following manner:

[0196] Assuming the base station is located at point A(0,0,z0), the orientation angle and elevation angle of the positioning tag relative to the base station are obtained through direction finding. Then the measured coordinates P of the positioning tag can be calculated:

[0197]

[0198] Where z is the height of the positioning label;

[0199] Rotate the measured coordinates P(x,y,z) of the positioning tag using a rotation matrix R to obtain point P':

[0200]

[0201] Calculate the intersection point Pr(X1,Y1,z) of the straight line determined by base station A and point P' and the horizontal plane where the positioning tag is located;

[0202] Based on the actual location of the base station, calculate the actual location of the positioning tag: (X1+x0,Y1+y0,z).

[0203] Accordingly, other embodiments of this application may also provide a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the various method embodiments of this application. Computer-readable storage media include permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information may be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0204] In summary, this invention measures the attitude of an array antenna by using positioning tags to obtain attitude angles and complete attitude calibration. It is low-cost, highly efficient, and suitable for a wide range of applications.

[0205] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An attitude calibration method for an array direction-finding antenna, characterized in that, include: Accurately measure the true coordinates of the center point A of the array antenna; Positioning tags are placed around the array antenna, and the true coordinates Pr of N sets of positioning tags and the azimuth angles of N sets of positioning tags relative to the array antenna are measured. and pitch angle ; Obtain the measurement coordinates P of N sets of the positioning tags. ; Obtain the rotated coordinates P' of each of the measured coordinate points P. ; Calculate the rotation matrix R using the N sets of coordinates of P and P'; The attitude angle of the array antenna is obtained using the rotation matrix R; The process of obtaining the measurement coordinates P of N sets of positioning tags includes: using the true coordinates of the center point A of the array antenna in one set. N sets of the azimuth angle and the pitch angle and the actual coordinates of the N sets of positioning tags Calculate the measurement coordinates P of the positioning tag.

2. The attitude calibration method for an array direction-finding antenna as described in claim 1, characterized in that, The elevation angle of the positioning tag relative to the array antenna The range is from 20 degrees to 50 degrees.

3. The attitude calibration method for an array direction-finding antenna as described in claim 1, characterized in that, The array antenna collects data and uploads it to the server. The server performs direction finding processing on the positioning tag to obtain the orientation angle. and pitch angle .

4. The attitude calibration method for an array direction-finding antenna as described in claim 1, characterized in that, The process of obtaining the measurement coordinates P of the N sets of positioning tags also includes: The center point A of the array antenna Translation Then the actual coordinates Pr of the positioning tag also become: ， Recorded as: When the array antenna is located When the height of the positioning tag is Zi, the height difference between the positioning tag and the array antenna is z0-Zi, which is determined by the azimuth angle. and pitch angle Determine the coordinates of the location tag's measurement coordinates P: Obtain the measurement coordinates P of the N sets of positioning tags: 。 5. The attitude calibration method for an array direction-finding antenna as described in claim 4, characterized in that, The process of obtaining the rotated coordinates P' of each of the measured coordinates P points includes: connecting the center point A of the array antenna with the real coordinates Pr of the positioning tag to obtain a line segment APr; rotating the horizontal plane through the rotation matrix R to obtain a plane; the intersection of the line segment APr and the plane is P'; and P' is the point P after being rotated through the rotation matrix R. Through the coordinates of point A Coordinates of point P get: The actual coordinates of the positioning tag as well as The length of P' is calculated, and its coordinates are given by [reference to P']. ; From the actual coordinates of the N sets of positioning tags, obtain the N sets of P' coordinates: 。 6. The attitude calibration method for an array direction-finding antenna as described in claim 5, characterized in that, The process of calculating the rotation matrix R using the N sets of coordinates of P and P' includes obtaining the rotation matrix R through the SVD decomposition method.

7. The attitude calibration method for an array direction-finding antenna as described in claim 6, characterized in that, The process of obtaining the rotation matrix R includes: N sets of coordinates of point P ； N sets of coordinates of point P': ； The average value of N sets of P coordinates: , The average of N sets of P' coordinates: ; Normalize all points: ， ， Calculate the covariance matrix: Where A and B respectively represent the terms... and Let be a matrix composed of columns, and let the dimension of the matrix be . ; Compute the singular value decomposition of matrix S Then the rotation matrix R: det represents the determinant of a matrix, and V is the matrix S. T The matrix formed by the eigenvectors of S.

8. The attitude calibration method for an array direction-finding antenna as described in claim 7, characterized in that, The process of obtaining the attitude angle of the array antenna using the rotation matrix R includes: calculating the attitude angle using a formula. ； in, This indicates the angle by which the array antenna rotates around the Z-axis of the map coordinate system; The angle by which the array antenna rotates around the X-axis of the map coordinate system; The angle by which the array antenna rotates around the Y-axis of the map coordinate system; The m-th row and n-th column terms in the rotation matrix R.

9. The attitude calibration method for an array direction-finding antenna as described in claim 8, characterized in that, Also includes: The measurement coordinates of the positioning tag are calibrated using a rotation matrix R.

10. The attitude calibration method for an array direction-finding antenna as described in claim 9, characterized in that, The calibration of the measurement coordinates of the positioning tag using the rotation matrix R includes: When the base station is located at point A The azimuth and elevation angles of the positioning tag relative to the base station are obtained through direction finding. Calculate the measured coordinates P of the positioning tag: Where z is the height of the positioning label; Use rotation matrix R to locate the measured coordinates P of the tag. Rotate to obtain point P': Calculate the intersection point P of the straight line determined by base station A and point P' with the horizontal plane where the positioning label is located. ; By combining the actual location of the base station, the actual location of the positioning tag is calculated: .

11. An attitude calibration system for an array direction-finding antenna, characterized in that, include: Orientation finding module, calculation module, and attitude angle acquisition module; The direction-finding module is used to accurately measure the true coordinates of the center point A of the array antenna, the true coordinates of the positioning tag, and the azimuth angle of the positioning tag relative to the array antenna. and pitch angle ; The calculation module is used to utilize the true coordinates of the center point A of the array antenna measured by the direction-finding module and the direction angle. and pitch angle The measured coordinates P of the positioning tag and the coordinates P' of the measured coordinates P after rotation are obtained by accurately calculating the actual coordinates of the positioning tag. The attitude angle acquisition module is used to obtain the rotation matrix R by using the coordinates of P and P' calculated by the calculation module.

12. The attitude calibration system for an array direction-finding antenna as described in claim 11, characterized in that, It also includes a calibration module, which is used to calibrate the coordinates of the positioning tag using the rotation matrix R.

13. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions that, when executed by a processor, implement the steps of the method as described in any one of claims 1 to 10.

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